At the end of the council most of the Byzantines had agreed to the compromises. One of the participants opposed to union, Patriarch Joseph, died before the negotiations finished. 17 Thus, by the conclusion of the meeting, only a singular dissenter, Mark of Ephesus, remained from the Orthodox delegation. Perhaps the most important aspect of the declaration was a recognition of the Pope as the “head of the whole church.” 18 The Emperor signed the declaration and headed back to Constantinople where he hoped the city would receive it warmly. Shortly after returning to the city, the declaration was read aloud in the Cathedral of the Assumption. However, rather than being met with a welcome reception, most of the Orthodox clergy of the city refused to submit to the new declaration and instead gathered around the singular dissenter, Mark of Ephesus. Following this cold reception, many of the signatories who were present in Florence also reneged. 19 While a union was achieved on paper in Florence, the Orthodox clergy begrudged these new doctrinal commitments and so abandoned them. The impending Ottoman threat was far less potent than yielding to Latin decrees in order to receive their aid. Saliently, the Orthodox refused to compromise with Latin authorities, despite the looming threat of invasion. The bitterness towards the Pope was greater than their enmity to the invading Sultan. Such attitudes suggest inner dissension was greater than any idea of unity against a single enemy.

SEED: Angle for an essay: why doctrinal identity can outweigh existential security threats — the Florence precedent for why forced alliances fracture under pressure. XREF: Connects to the broader schism between Eastern and Western Christianity and the enduring Orthodox suspicion of papal authority.

Ali Qureshi, The Fall of Constantinople, loc. 38